Detailed Description

A menu bar consists of a list of pull-down menu items. You add menu items with addMenu(). For example, asuming that menubar is a pointer to a QMenuBar and fileMenu is a pointer to a QMenu, the following statement inserts the menu into the menu bar:

menubar->addMenu(fileMenu);

The ampersand in the menu item's text sets Alt+F as a shortcut for this menu. (You can use "&&" to get a real ampersand in the menu bar.)

There is no need to lay out a menu bar. It automatically sets its own geometry to the top of the parent widget and changes it appropriately whenever the parent is resized.

Usage

In most main window style applications you would use the menuBar() function provided in QMainWindow, adding QMenus to the menu bar and adding QActions to the pop-up menus.

Widgets can be added to menus by using instances of the QWidgetAction class to hold them. These actions can then be inserted into menus in the usual way; see the QMenu documentation for more details.

Platform Dependent Look and Feel

Different platforms have different requirements for the appearance of menu bars and their behavior when the user interacts with them. For example, Windows systems are often configured so that the underlined character mnemonics that indicate keyboard shortcuts for items in the menu bar are only shown when the Alt key is pressed.

QMenuBar as a Global Menu Bar

On macOS and on certain Linux desktop environments such as Ubuntu Unity, QMenuBar is a wrapper for using the system-wide menu bar. If you have multiple menu bars in one dialog the outermost menu bar (normally inside a widget with widget flag Qt::Window) will be used for the system-wide menu bar.

Qt for macOS also provides a menu bar merging feature to make QMenuBar conform more closely to accepted macOS menu bar layout. The merging functionality is based on string matching the title of a QMenu entry. These strings are translated (using QObject::tr()) in the "QMenuBar" context. If an entry is moved its slots will still fire as if it was in the original place. The table below outlines the strings looked for and where the entry is placed if matched:

String matches

Placement

Notes

about.*

Application Menu | About <application name>

The application name is fetched from the Info.plist file (see note below). If this entry is not found no About item will appear in the Application Menu.

Note: The text used for the application name in the macOS menu bar is obtained from the value set in the Info.plist file in the application's bundle. See Qt for macOS - Deployment for more information.

Note: On Linux, if the com.canonical.AppMenu.Registrar service is available on the D-Bus session bus, then Qt will communicate with it to install the application's menus into the global menu bar, as described.

Property Documentation

defaultUp : bool

This property holds the popup orientation

The default popup orientation. By default, menus pop "down" the screen. By setting the property to true, the menu will pop "up". You might call this for menus that are below the document to which they refer.

If the menu would not fit on the screen, the other direction is used automatically.

Access functions:

bool

isDefaultUp() const

void

setDefaultUp(bool)

nativeMenuBar : bool

This property holds whether or not a menubar will be used as a native menubar on platforms that support it

This property specifies whether or not the menubar should be used as a native menubar on platforms that support it. The currently supported platforms are macOS, and Linux desktops which use the com.canonical.dbusmenu D-Bus interface (such as Ubuntu Unity). If this property is true, the menubar is used in the native menubar and is not in the window of its parent; if false the menubar remains in the window. On other platforms, setting this attribute has no effect, and reading this attribute will always return false.

The default is to follow whether the Qt::AA_DontUseNativeMenuBar attribute is set for the application. Explicitly setting this property overrides the presence (or absence) of the attribute.

This convenience function creates a new action with the given text. The action's triggered() signal is connected to the receiver's member slot. The function adds the newly created action to the menu's list of actions and returns it.

This convenience function creates a new action with the given text. The action's triggered() signal is connected to the method of the receiver. The function adds the newly created action to the menu's list of actions and returns it.

This convenience function creates a new action with the given text. The action's triggered() signal is connected to the functor. The function adds the newly created action to the menu's list of actions and returns it.

void QMenuBar::clear()

Removes all the actions from the menu bar.

Note: On macOS, menu items that have been merged to the system menu bar are not removed by this function. One way to handle this would be to remove the extra actions yourself. You can set the menu role on the different menus, so that you know ahead of time which menu items get merged and which do not. Then decide what to recreate or remove yourself.

Initialize option with the values from the menu bar and information from action. This method is useful for subclasses when they need a QStyleOptionMenuItem, but don't want to fill in all the information themselves.

This convenience function creates a new separator action, i.e. an action with QAction::isSeparator() returning true. The function inserts the newly created action into this menu bar's list of actions before action before and returns it.

This sets the given widget to be shown directly on the left of the first menu item, or on the right of the last menu item, depending on corner.

The menu bar takes ownership of widget, reparenting it into the menu bar. However, if the corner already contains a widget, this previous widget will no longer be managed and will still be a visible child of the menu bar.

This signal is emitted when an action in a menu belonging to this menubar is triggered as a result of a mouse click; action is the action that caused the signal to be emitted.

Note: QMenuBar has to have ownership of the QMenu in order this signal to work.

Normally, you connect each menu action to a single slot using QAction::triggered(), but sometimes you will want to connect several items to a single slot (most often if the user selects from an array). This signal is useful in such cases.